Active matrix type liquid crystal display device and manufacturing process for the same

ABSTRACT

An active matrix liquid crystal display device of the invention includes a liquid crystal display panel operating in a normally black mode having a first substrate provided with a color filter and a second substrate provided with an active matrix array, wherein the first substrate is provided with a laminated colored layer with three colors, a laminated colored layer with two colors and a colored layer with one color in a frame part surrounding a display area without being provided with a black matrix, and the second substrate is provided with a conductive film formed in a region which is opposed to the laminated colored layer with two colors and the colored layer with one color, between the display area and the laminated colored layer with three colors.

INCORPORATION BY REFERENCE

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2008-010869, filed on Jan. 21, 2008, andNo. 2008-322092, filed on Dec. 18, 2008, the disclosure of which isincorporated herein in its entirety by reference.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to an active matrix liquid crystal display(LCD) device and a manufacturing process for the same and in particular,relates to an active matrix liquid crystal display device with alight-shielding structure formed by laminating color layers instead of ablack matrix and a manufacturing process for the same.

2. Background Art

In recent years, it is strongly required that an active matrix LCDdevice with a high display quality can be obtained at smaller cost.

In a related LCD device, in order to shield a light entered from a framepart, a light shielding layer called a black matrix (BM) is formed on asubstrate having a color filter (color filter substrate). Thisblackmatrix consists of a metal such as a chrome (chrome oxide) or aresin or the like. However, in order to decrease manufacturing costs, atechnology for omitting the black matrix is proposed. For example, anLCD device which has a light shielding layer on a frame part surroundinga display area is disclosed in Japanese Patent Application Laid-Open No.2000-29014 and Japanese Patent Application Laid-Open No. 2003-14917. Thelight shielding layer is formed by laminating colored layers whichconsist of at least two colors out of the plural colors.

FIG. 5 shows an outside plan view of a panel in a related common LCDdevice. FIG. 6 is a cross-sectional view along the VI-VI line in FIG. 5and shows a structure of the LCD device having a black matrix. On theother hand, FIG. 7 shows the structure of a color filter substrate ofthe related LCD device where the black matrix is omitted, and FIG. 7 isalso a cross-sectional view along the VI-VI line in FIG. 5.

As shown in FIG. 5, the related LCD device includes a display area 1where a pixel is formed and a frame part 2 which surrounds the displayarea 1. As shown in FIG. 6, in order to hide wirings which are formed onan array substrate 30A and are drawn out from the display area 1, ablack matrix 25 is formed on the frame part 2 of a color filtersubstrate 20A in which a color filter is formed. In this structure, theframe part 2 around the display area 1 is shielded from a light by theblackmatrix 25. Therefore, even though an electric field is appliedbetween the wirings, deterioration of the display quality in the framepart 2 because of the light transmitted through this part does notarise.

On the other hand, as shown in FIG. 7, a color filter substrate 20B isnot provided with a black matrix, but a light shielding structure isformed by laminating two or more colored layers. That is, the frame part2 is shielded from a light by laminated structure composed of the samecolored layers as those of the display area 1 (for example, red (R)colored layer 21, green (G) colored layer 22, and blue (B) colored layer23).

SUMMARY

An exemplary object of the invention is to provide an active matrix typeLCD device in which a frame part is sure to be shielded from a light bya laminated structure of colored layers instead of a black matrix andwhose development costs can be reduced.

An active matrix LCD device according to an exemplary aspect of theinvention includes a liquid crystal display panel operating in anormally black mode having a first substrate provided with a colorfilter and a second substrate provided with an active matrix array,wherein the first substrate is provided with a laminated colored layerwith three colors, a laminated colored layer with two colors and acolored layer with one color in a frame part surrounding a display areawithout being provided with a black matrix, and the second substrate isprovided with a conductive film formed in a region which is opposed tothe laminated colored layer with two colors and the colored layer withone color, between the display area and the laminated colored layer withthree colors.

An active matrix LCD device according to another exemplary aspect of theinvention includes a liquid crystal display panel operating in anormally black mode having a first substrate provided with a colorfilter and a second substrate provided with an active matrix array,wherein the first substrate is provided with a laminated colored layerwith three colors, a laminated colored layer with two colors, and acolored layer with one color in a frame part surrounding a display areawithout being provided with a black matrix, and the second substrate isprovided with a conductive film formed in a region which is opposed to aboundary part between the display area and the colored layer with onecolor, and a boundary part between the laminated colored layer withthree colors and the laminated colored layer with two colors.

A manufacturing process of an active matrix LCD device according to anexemplary aspect of the invention includes the steps of forming a colorfilter substrate by means of forming a first colored layer using alithography process with an exposure mask, forming a second color layerusing a lithography process with a mask having a same pattern as theexposure mask, and forming a third colored layer using a lithographyprocess with a mask having a same pattern as the exposure mask, forminga conductive film in a region on an array substrate which is opposed toa colored layer with one color and a laminated colored layer with twocolors which are located in an outer circumference of a display area onthe color filter substrate, sticking the color filter substrate on thearray substrate, and sealing a liquid crystal inserted therebetween.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary features and advantages of the present invention will becomeapparent from the following detailed description when taken with theaccompanying drawings in which:

FIG. 1 is a cross-sectional view showing a structure near a frame partof an active matrix type LCD device of a first example of the presentinvention;

FIG. 2 is a cross-sectional view showing a structure near a frame partof an active matrix type LCD device of a second example of the presentinvention;

FIG. 3 is a plan view showing the structure near a frame part of theactive matrix type LCD device of the second example of the presentinvention;

FIG. 4 is a cross-sectional view showing a structure near a frame partof an active matrix type LCD device of a third example of the presentinvention;

FIG. 5 is a plan view showing a structure of a related liquid crystaldisplay panel;

FIG. 6 is a cross-sectional view showing a structure near a frame partof a related active matrix type LCD device having a black matrix; and

FIG. 7 is a cross-sectional view showing a structure near a frame partof a color filter substrate of a related active matrix type LCD devicewhere a black matrix is omitted.

EXEMPLARY EMBODIMENT

Exemplary embodiments of the present invention will now be described indetail in accordance with the accompanying drawings.

A FIRST EXAMPLE

An active matrix type liquid crystal display (LCD) device according to afirst example of the present invention is provided with a liquid crystallayer which operates by a normally black mode, and has a structure of aframe part which includes colored layers. The colored layers in theframe part consist of at least two colors among three colors of R, G,and B which are formed by shift exposure using a same mask. Atransparent electrode is arranged covering a region on an arraysubstrate which is opposed to a colored layer part where a colored layerconsisting of only one color or two kinds of color is formed in a regionbetween a display area and a colored layer consisting of three kinds ofcolor.

According to such structure, an electric field is not applied to aliquid crystal in the colored layer part in the frame part consisting ofone color or two kinds of color, so normally black mode of an LCD panelis maintained. Therefore, the light transmitted through this regionhardly arises, and good display quality can be secured. Even though alight enters this region from outside, since reflection of light hardlyarises in this region, display quality can be kept excellent.

Common electrode potential is desirably applied to the transparentelectrode or an opaque electrode formed in this region. Thereby, sincethe liquid crystal of this region is further stabilized, light leakageis further suppressed and the display quality of the frame part can bekept more excellent.

Next, the first example of the present invention is described in detailusing a drawing. FIG. 1 is a cross-sectional view showing schematicallya structure near the frame part of the active matrix type LCD deviceaccording to this example.

As shown in FIG. 1, an LCD device 10 according to this example has anarray substrate 30, a color filter substrate 20 which is opposed to thearray substrate 30, a liquid crystal layer 50 inserted between the bothsubstrates, and a seal 40 which joins both substrates and seals theliquid crystal layer 50. The array substrate 30 has an array pattern 31in which pixels having switching elements such as TFTs (thin filmtransistors) are arranged in a matrix shape. A colored layercorresponding to each color is arranged in a display area 1 of the colorfilter substrate 20 opposed to each pixel of the array substrate 30. Oneor more color layers are formed in the frame part 2 around the displayarea 1, and an overcoat layer 24 is formed so that these color layerscan be covered. Polarizing plates 26 and 34 are arranged on the face ofthe array substrate 30 and the color filter substrate 20 on the oppositeside of the liquid crystal layer 50, respectively.

Here, in this example, each colored layer is formed by exposure processusing a common mask for each color of R, G, and B. That is, for example,the same mask is used for forming the colored layer of R and Brespectively as is used for forming the colored layer of G. The maskconsists of a pattern for a colored layer in the display area and apattern for a colored layer in the frame part. In this case, in thedisplay area 1, an exposure process is performed by means of shiftingthe mask by one pixel size for every colored layer. At that time, sinceeach colored layer pattern corresponding to the frame part 2 is alsoformed by means of shifting the same mask, each colored layer pattern ofR, G, and B in the frame part 2 is not uniform at its edge and is formedshifted by one pixel. As a result, as shown in FIG. 1, a main regionexcept both edge regions in the frame part 2 consists of two or morecolored layers (in this example, three colored layers 21-23 for threecolors of RGB). This part has a high light shield effect, and thisregion becomes an achromatic color, therefore this part functions as asubstitution of a black matrix perfectly. On the other hand, in the bothedge regions of the frame part 2, the region which consists of a coloredlayer with only one color or overlapping colored layers with differenttwo colors respectively is formed. That is, in the frame part 2, thecolored layers which consist of two layers with two colors respectively(for example, R and G, or G and B) is formed so that the main regionwhere the colored layers consist of three layers with three colors maybe surrounded therewith, and the colored layer which consists of onelayer with only one color of R or B is formed so that the colored layerswith two colors may be surrounded therewith.

Generally, the laminated part of the colored layer with one color or twocolors does not have light shield effect enough. Therefore, when anelectric field arises in the array substrate 30 side, the liquid crystalmoves in the region and the view of the motion can be visuallyrecognized through the colored layer with one color or two colors. As aresult, display quality is made lower.

However, in this example, in the region between the colored layer withthree colors in the frame part 2 and the display area 1, a transparentelectrode 32 is arranged covering the region on the array substrate 30which is opposed to the colored layer with one color or two colors.Thereby, the electric field in peripheral regions can be prevented fromentering into this region, and the normally black state of the liquidcrystal is maintained because the polarizing plates 26 and 34 are formedalso in the region corresponding to the transparent electrode 32.Therefore, also in the part where the colored layer with only one coloror two colors is formed, the light transmitted through this regionhardly arises and degradation of display quality can be prevented.Therefore, according to the LCD device of this example, a manufacturingcost can be reduced by using a common mask for RGB, and display qualitycan be kept excellent because the frame part is sure to be shielded fromlight.

If needed, this transparent electrode 32 may be electrically connectedto a common electrode wiring on an LCD panel, and potential of thetransparent electrode 32 may be made equal to that of the commonelectrode. Thereby, since the liquid crystal layer can be furtherstabilized, the light transmitted through the region in which thecolored layer with only one color or two colors is formed can beprevented more certainly.

Next, a manufacturing process of the LCD device of the above-mentionedstructure is described. First, a manufacturing process of the colorfilter substrate 20 is described.

Firstly, after applying the resist used as the colored layer of G, the Gcolored layer 22 is formed by performing exposure using the mask with acolored layer pattern of G for the display area 1 and a frame partpattern, and by developing and baking.

Next, the R colored layer 21 is formed by exposing the resist used asthe colored layer of R with the same mask shifted leftward in FIG. 1 byone pixel, and by developing and baking.

The B colored layer 23 is formed by exposing the resist used as thecolored layer of B with the same mask shifted rightward in FIG. 1 by onepixel, and by developing and baking. In this specification, each pixelfor the R, G, or B is called one pixel.

The same mask is used in this example as mentioned above. However, inthe case of forming a marker part, only when the resist for the Gcolored layers 22 as the first layer is exposed, the resist thereof isalso exposed using the pattern for the marker. In the case of exposingsecond layer and third layer, the colored layer of the second layer andthe third layer in the marker part is removed by shielding the part nearthe marker. By this process, in the display area 1 and near the edge ofthe frame part 2, the colored layer for RGB is formed shifted by onepixel size. On the other hand, in the marker part near surrounding area,only the marker of the first layer is formed and it has a completelydifferent pattern. By adopting this structure, each colored layer forRGB can be formed with the same mask; and manufacturing costs can bereduced.

The thickness of each colored layer is determined so that a chromaticityrange will be 40% on the condition of displaying. More specifically, thethickness of the R colored layer, the G colored layer, and the B coloredlayer is set at about 1.0 μm, respectively. When these three coloredlayers are piled up, transmission factor thereof is about 1% or less andthe light shield effect is sufficient for a substitution of a blackmatrix.

Next, a transparent acrylic resin used as an overcoat layer is appliedon this colored layer and is baked. Columnar spacers (not shown inFIG. 1) consisting of acrylic resin are formed on the overcoat layer. Asa consequence of the above, the color filter substrate 20 is formed.

In this example, although the colored layers of three colors arelaminated in order of G, R, and B respectively, the laminating orderthereof can be changed. The columnar spacers may be formed in the arraysubstrate 30 side. Spherical spacers may be applied instead of thecolumnar spacers.

Next, a manufacturing process of the array substrate 30 is explained.The manufacturing process of the array substrate 30 is the same as thatof a conventional active matrix type array substrate using a-Si TFT as aswitching element. For example, the array substrate 30 can bemanufactured by the following processes.

First, a first metal layer (such as opaque metal) used as a scanningwiring and a common wiring is processed into a predetermined pattern.After a gate insulating film and a thin film semiconductor layer areformed, this thin film semiconductor layer is processed into anisland-shaped part which is used as a switching element.

Next, a second metal layer used as a video signal wiring is processedinto a predetermined pattern, and the contact layer in the island-shapedsemiconductor layer is etched by using the wiring pattern.

After forming an insulating layer serving as a passivation layer, athrough-hole for contact is formed. Next, a comb-tooth electrode whichconsists of a pixel electrode and a common electrode is formed by usingan ITO (indium tin oxide) as a transparent conductive film. This pixelelectrode is connected to a drain electrode of the TFT formed by thesecond metal layer, and the common electrode is connected to the commonelectrode wiring formed by the first metal layer.

Here, the region in the array substrate 30 which is opposed to the partof the colored layer with one color and the laminated part of coloredlayers with two colors in the frame part 2 of the color filter substrate20 is formed so that it may be covered by the ITO layer. If needed, thetransparent electrode 32 formed by this ITO layer is connected to thecommon electrode wiring which consists of the first metal layer via athrough-hole. Although the structure is shown in FIG. 1 where thetransparent electrode 32 is formed so that it may be projected from theabove-mentioned region, it is not limited to this structure and it iseffective that the transparent electrode 32 may just cover the coloredlayer region with one color and the laminating region of the coloredlayers with two colors at least.

An alignment film is formed on the color filter substrate 20 and thearray substrate 30 and rubbing treatment is performed in a predetermineddirection. Then, the color filter substrate 20 and the array substrate30 are stuck, and the liquid crystal is inserted in and sealed. Theliquid crystal is homogeneously aligned, and polarizing plates arearranged with cross-Nicol relationship so that a normally black mode isobtained. In this example, an IPS (In-Plain Switching) mode LCD deviceis used which is driven by an electric field parallel to the substrateapplied between the pixel electrode and the common electrode.

The LCD device according to the present invention is obtained bysticking polarizing plates on both sides and finally, connecting apredetermined circuit to this liquid crystal panel.

Thus, in the region on array substrate 30 which is opposed to thecolored layer part with one color and the laminated part of the coloredlayers with two colors, the transparent electrode 32 is arranged so thatthis region can be covered. The potential on this transparent electrode32 is fixed to common electrode potential if needed. Therefore, anelectric field is not applied to the liquid crystal of this region. As aconsequence, even though the mask used for forming each colored layer ofRGB is shared, a normally black mode can be maintained. Therefore, thelight transmitted through the frame part 2 hardly arises and the framepart 2 can be surely shielded from light.

Even though an opaque metallic layer is arranged instead of thetransparent electrode 32, a normally black mode can be maintainedbecause an electric field is not applied to the liquid crystal in theframe part 2. However, when an outside light enters through the colorfilter substrate 20, the light transmitted through the polarizing plate26 in the color filter substrate 20 passes through the liquid crystallayer 50 in a polarization condition almost as it is, and is reflectedwith this opaque metal layer. Because this reflected light passesthrough the liquid crystal layer 50 with the polarization conditionmaintained and emits from the polarizing plate in the color filtersubstrate 20, a specific colored reflected light can be seen and theimage quality is remarkably damaged. Therefore, in the LCD device ofthis example, it is desirable to arrange a layer consisting of thematerial with a low reflectance to visible light (for example, atransparent conductive film, such as an ITO).

The colored layer part with one color and the laminated part of thecolored layers with two colors are formed in the shifted direction ofthe mask. And, in the direction which intersects perpendicularly withthe shifted direction of the mask, the frame part 2 is provided onlywith the laminated colored layer with three kinds of colors. Therefore,the transparent electrode 32 needs not necessarily arranging to itsdirection. When the mask is slantingly shifted to the edge of the arraysubstrate 30, the colored layer part with one color and the laminatedcolored layer with two colors are formed in the perimeter of the framepart 2, therefore, in this case, the transparent electrode 32 can bearranged in the perimeter of the frame part 2.

A SECOND EXAMPLE

An active matrix type liquid crystal display device according to asecond example of the present invention is provided with a liquidcrystal layer which operates by a normally black mode, and has a framepart including colored layers with at least two colors among threecolors of R, G, and B which are formed by shifted exposure process witha same mask. In a region of an array substrate which is opposed to aboundary part between a colored layer part with one color or a laminatedcolored layer with two colors in a frame part and a display area, and aboundary part between the colored layer part with one color or thelaminated colored layer with two colors in the frame part and alaminated colored layer with three colors in the frame part, atransparent electrode or opaque electrode which covers this boundarypart at least is arranged.

Next, the second example of the present invention is described in detailusing a drawing. FIG. 2 is a cross-sectional view showing schematicallya structure near the frame part of the active matrix LCD deviceaccording to this example, and FIG. 3 is a plan view looked from anupper part near the frame part.

A main region except both edge regions in the frame part 2 is providedwith a three-layer laminated structure consisting of three colored layerwith each layer having respectively one color among three colors of RGB,as well as the active matrix type LCD device according to the firstexample. This region functions as a substitution of a black matrixperfectly because transmission factor thereof is very small. On theother hand, a colored layer part with one color or overlapping coloredlayers with two colors are formed in the both edge regions of the framepart 2.

Generally, the colored layer part with one color or the laminatedcolored layer with two colors does not have light shield effect enough.Therefore, when an electric field arises in the array substrate 30 side,the liquid crystal moves in the region and the view of the motion can bevisually recognized through the colored layer with one color or twocolors. As a result, display quality is made lower.

However, in this example, as shown in FIG. 2 and FIG. 3, a transparentelectrode 32 is formed in a surrounding region of the colored layer partwith one color, or the laminated colored layer with two colors. Morespecifically, a transparent electrode 32 is arranged in a region on thearray substrate which is opposed to a boundary part in the frame partbetween a display area 1 and a colored layer part with one color or alaminated colored layer with two colors, and a boundary part in theframe part between a laminated colored layer with three colors and thecolored layer part with one color or the laminated colored layer withtwo colors. The transparent electrode 32 can be arranged if needed alsoin a region which is opposed to a wiring (for example, a scanning wiringor a video signal wiring) with different potential from common electricpotential. If needed, this transparent electrode 32 may be connected tothe common electrode wiring, and the potential thereof may be fixed tothe common electrode potential. The width of transparent electrode 32 isnot limited in particular, and it should have width which covers atleast the boundary part (and if required the above-mentioned wiringpart).

By adopting the structure, an electric field is not applied to theliquid crystal in the region surrounded with the transparent electrode32. Because polarizing plates 26 and 34 are formed also in the regioncorresponding to the transparent electrode 32, a normally black mode ismaintained. Therefore, even though a mask for forming each colored layerof RGB is shared, a light cannot be transmitted through this region andthe frame part 2 can be surely shielded.

In the first example, when the opaque metal layer is arranged instead ofthe transparent electrode, the outside light which enters through thecolor filter substrate 20 is reflected by this metal layer. As a result,the image quality is damaged.

In this example, in contrast to it, the area of the electrode in theframe part is small enough compared with that of the first example.Therefore, reflection of the outside light in this region hardly arises.Therefore, in this example, instead of the transparent electrode 32, anopaque electrode 33 can be used. The opaque electrode 33, for example,consists of the first metal layer used as a scanning line and commonwiring, or the second metal layer used as a video signal wiring.

In this example, in the direction which intersects perpendicularly withthe shifted direction of the mask, the frame part 2 is provided onlywith the laminated colored layer with three kinds of colors. Therefore,the transparent electrode 32 or the opaque electrode 33 needs notnecessarily arranging to its direction. When the mask is slantinglyshifted to the edge of the array substrate 30, the transparent electrode32 or the opaque electrode 33 can be arranged in the perimeter of theframe part 2.

A THIRD EXAMPLE

Next, an active matrix LCD device concerning according to a thirdexample of the present invention is explained with reference to FIG. 4.FIG. 4 is a cross-sectional view showing schematically a structure neara frame part of an active matrix LCD device of this example.

As shown in FIG. 4, an LCD device 10 according to this example has anarray substrate 30, a color filter substrate 20 which is opposed to thearray substrate 30, a liquid crystal layer 50 inserted between the bothsubstrates, and a seal 40 which joins both substrates and seals theliquid crystal layer 50 as well as the first example. The colored layerwith each color which is opposed to each pixel of the array substrate 30is arranged in a display area 1 in the color filter substrate 20. Acolor layer part with one layer or a laminated part with a plurality ofcolor layers is formed in a frame part 2 surrounding the display area 1,and an overcoat layer 24 is formed so that these color layer parts maybe covered. Polarizing plates 26 and 34 are arranged on the face of thearray substrate 30 and the color filter substrate 20 on the oppositeside of the liquid crystal layer 50, respectively.

Here, in this example, in forming the colored layer with each color, onemask for exposure process is shared to form the colored layers with twocolors among the three colors of R, G, and B, and an another mask forexposure process is used to form the colored layer with the remainingone color. That is, in this example, one mask is used to expose thecolored layer of G first, and the other mask is used to expose to thecolored layer with the remaining colors of R and B.

Also in this example, a main region except both edge regions in theframe part 2 has laminated colored layer with three colors of RGB. Thisregion functions as a substitution of a black matrix perfectly, becausethe light transmission factor in this region is very small.

On the other hand, as shown in FIG. 4, between the main region and thedisplay area 1, the laminated colored layer with two colors of R and Gis formed. The laminated colored layer with two colors of G and B andthe colored layer with only one color of B are formed in the outercircumference area of the main region.

Generally, the laminated part of the colored layer with one color or twocolors does not have light shield effect enough. Therefore, when anelectric field arises in the array substrate 30 side, the liquid crystalmoves in the region and the view of the motion can be visuallyrecognized through the colored layer with one color or two colors. As aresult, display quality is made lower.

However, in this example, in the region between the display area 1 andthe laminated colored layer with three colors in frame part 2, atransparent electrode 32 is arranged covering the region on the arraysubstrate 30 which is opposed to the laminated colored layer with twocolors. Thereby, the electric field in peripheral regions can beprevented from entering into this region, and the normally black stateof the liquid crystal is maintained because the polarizing plates 26 and34 are formed also in the region corresponding to the transparentelectrode 32. Therefore, also in the region where the colored layer withonly one color or two colors is formed, the light transmitted throughthis region hardly arises and degradation of display quality can beprevented.

As mentioned above, according to this example, a manufacturing cost canbe reduced by using a common mask for RGB, and display quality can bekept excellent because the frame part is sure to be shielded from light.

If needed, the transparent electrode 32 is electrically connected to thecommon electrode wiring on the LCD panel, and the potential thereof canbe equal to the common electrode potential. Thereby, since the liquidcrystal of this region is further stabilized, the light transmittedthrough the colored layer with one color or the colored layer with twocolors is sure to be further suppressed.

Next, a manufacturing process of the LCD device according to thisexample is explained. First, a manufacturing process of the color filtersubstrate 20 is described.

After applying the resist used as the colored layer of G firstly, the Gcolored layer 22 is formed by exposing with the mask which contains acolored layer pattern of G in the display area 1 and a frame partpattern, and by developing and baking. Next, a resist used as thecolored layer of R is exposed with a different mask from that used forthe colored layer of G, and by developing and baking, the R coloredlayer 21 is formed. The resist used as the colored layer of B is exposedwith the same mask used in forming the R colored layer 21 shiftedrightward of FIG. 4 by two pixels, and by developing and baking, the Bcolored layer 23 is formed.

Here, a marker is formed in a mask for exposing the G colored layer, anda marker is not formed in a mask for the R colored layer and the Bcolored layer.

By the above-mentioned process, each colored layer of RGB has thestructure shifted by pixel size in the display area 1, and, on the otherhand, a completely different pattern is formed in a surrounding markerregion. By adopting this structure, the R colored layer and the Bcolored layer can be formed with the same mask, therefore, manufacturingcosts can be reduced.

The thickness of each colored layer is determined so that a chromaticityrange will be 40% on the condition of displaying. More specifically, thethickness of the R colored layer, the G colored layer, and the B coloredlayer is set at about 1.0 μm, respectively. When these three coloredlayers are piled up, transmission factor thereof is about 1% or less andthe light shield effect is sufficient for a substitution of a blackmatrix.

Next, a transparent acrylic resin used as an overcoat layer is appliedon this colored layer and is baked. Columnar spacers consisting ofacrylic resin are formed. As a consequence of the above, the colorfilter substrate 20 is formed.

In this example, although the colored layers of three colors arelaminated in order of G, R, and B respectively, the laminating orderthereof can be changed. The columnar spacers may be formed in the arraysubstrate 30 side, and spherical spacers may be formed by a coatingprocess instead of the columnar spacers.

The array substrate 30 is formed as well as that of the first example.An alignment film is formed on the color filter substrate 20 and thearray substrate 30, respectively, and rubbing treatment is performed toeach alignment film in the predetermined direction. Then, the colorfilter substrate 20 and the array substrate 30 are stuck, and a liquidcrystal is inserted in and sealed. The LCD device according to thisexample is obtained by sticking polarizing plates on both sides andfinally, connecting a predetermined circuit to this liquid crystalpanel.

Thus, the transparent electrode 32 is arranged in the region on thearray substrate 30 which is opposed to the laminated colored layer withtwo colors so that the whole surface of this region can be covered.Because this transparent electrode 32 is fixed to common electrodepotential if needed, an electric field is not applied to the liquidcrystal. As a consequence, even though some masks used for forming eachcolored layer of RGB are shared, a normally black mode can bemaintained. Therefore, the light transmitted through the frame part 2hardly arises and the frame part 2 can be surely shielded from light.

In the first example, when the opaque metal layer is arranged instead ofthe transparent electrode, the outside light which enters through thecolor filter substrate 20 is reflected by this metal layer. As a result,the display quality is damaged.

In contrast to it, according to this example, since the laminatedcolored layer with two colors are formed in this region, even though anoutside light enters into this region, it is shielded by the laminatedcolored layer with two colors. Because reflected light hardly arises,there are no problems on display quality. Therefore, according to thisexample, both the transparent electrode 32 and the opaque electrode 33can be used.

In this example, in the direction which intersects perpendicularly withthe shifted direction of the mask, the frame part 2 is also providedonly with the laminated colored layer with three kinds of colors.Therefore, the transparent electrode 32 or the opaque electrode 33 needsnot necessarily arranging to its direction. When the mask is slantinglyshifted to the edge of the array substrate 30, the transparent electrode32 or the opaque electrode 33 can be arranged in the perimeter of theframe part 2.

In this example, as well as the first example, the transparent electrode32 is arranged so that the whole surface of the region can be covered.However, the transparent electrode in the boundary region of thelaminated colored layer according to the second example can be used withthe color filter substrate 20 according to this example. That is, thetransparent electrode 32 can be arranged in the region which is opposedto the boundary region between the laminated colored layer with twocolors and the display area 1, or the laminated colored layer with threecolors, and if needed, in the region which is opposed to a wiring regionwith potential different from common electric potential.

In above-mentioned examples, the colored layer pattern with three colorsof RGB is described. However, colored layer pattern consisting of fouror more colors can be used, and the trichromatic colored layer patternconsisting of colors other than RGB can be used similarly.

As disclosed in Japanese Patent Application Laid-Open No. 2000-29014 andJapanese Patent Application Laid-Open No. 2003-14917 which weredescribed in the background art, the technology of forming alight-shielding structure by laminating a plurality of colored layerswhich constitute a color filter without using a black matrix layer is aneffective process for cost reduction. However, in such related arts,because it is necessary to prepare a separate mask for each coloredlayer of RGB in order to form a satisfactory light-shielding structurein the frame part, there is a problem prevented from reducingmanufacturing costs.

That is, in the related LCD device, a pattern of a display color isformed in an opening area of each pixel to control color of the displayarea 1. When forming each of these colored layer patterns by exposingand developing a photosensitive resist, a mask for exposure is needed.To form all the frame parts by piling up the colored layers with threecolors, it is necessary to prepare the masks which consist of a displayarea pattern and a frame pattern corresponding to each colored layer ofR, G, and B, respectively. That is, because the mask patterns for eachcolored layer of R, G, and B are different each other, three kinds ofmasks are needed.

Thus, in the related LCD device, because a mask which has a differentpattern corresponding to each colored layer of R, G, and B, respectivelymust be used when a frame part is formed by piling up the colored layersof three colors, there is a problem of causing increase of developmentcosts.

An exemplary advantage according to the present invention is that in theactive matrix LCD device with the normally black mode without a blackmatrix layer, the frame part can be surely shielded from light, and themask used in forming each colored layer of RGB can be shared.

While the invention has been particularly shown and described withreference to exemplary embodiments thereof, the invention is not limitedto these embodiments. It will be understood by those of ordinary skillin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the present invention asdefined by the claims.

Further, it is the inventor's intention to retain all equivalents of theclaimed invention even if the claims are amended during prosecution.

1. An active matrix liquid crystal display device comprising: a liquid crystal display panel operating in a normally black mode including a first substrate provided with a color filter and a second substrate provided with an active matrix array, wherein said first substrate is provided with a laminated colored layer with three colors, a laminated colored layer with two colors and a colored layer with one color in a frame part surrounding a display area without being provided with a black matrix, and said second substrate is provided with a conductive film formed in a region which is opposed to said laminated colored layer with two colors and said colored layer with one color, between said display area and said laminated colored layer with three colors.
 2. An active matrix liquid crystal display device comprising: a liquid crystal display panel operating in a normally black mode including a first substrate provided with a color filter and a second substrate provided with an active matrix array, wherein said first substrate is provided with a laminated colored layer with three colors, a laminated colored layer with two colors, and a colored layer with one color in a frame part surrounding a display area without being provided with a black matrix, and said second substrate is provided with a conductive film formed in a region which is opposed to a boundary part between said display area and said colored layer with one color, and a boundary part between said laminated colored layer with three colors and said laminated colored layer with two colors.
 3. The active matrix liquid crystal display device according to claim 1, wherein a colored layer with each of three colors provided for said display area is formed by shifting a same mask for exposure in a predetermined direction.
 4. The active matrix liquid crystal display device according to claim 2, wherein a colored layer with each of three colors provided for said display area is formed by shifting a same mask for exposure in a predetermined direction.
 5. An active matrix liquid crystal display device comprising: a liquid crystal display panel operating in a normally black mode including a first substrate provided with a color filter and a second substrate provided with an active matrix array, wherein said first substrate is provided with a laminated colored layer with three colors, and a laminated colored layer with two colors in a frame part surrounding a display area without being provided with a black matrix, and said second substrate is provided with a conductive film formed in a region which is opposed to said laminated colored layer with two colors, between said display area and said laminated colored layer with three colors.
 6. An active matrix liquid crystal display device comprising: a liquid crystal display panel operating in a normally black mode including a first substrate provided with a color filter and a second substrate provided with an active matrix array, wherein said first substrate is provided with a laminated colored layer with three colors and a laminated colored layer with two colors in a frame part surrounding a display area without being provided with a black matrix, and said second substrate is provided with a conducting film formed in a region which is opposed to a boundary part between said display area and said laminated colored layer with two colors, and a boundary part between said laminated colored layer with three colors and said laminated colored layer with two colors.
 7. The active matrix liquid crystal display device according to claim 1, wherein said conductive film is fixed to a common potential.
 8. The active matrix liquid crystal display device according to claim 2, wherein said conductive film is fixed to a common potential.
 9. The active matrix liquid crystal display device according to claim 2, wherein said conductive film is fixed to a common potential and is also formed on a wiring with an electric potential different from said common potential in said second substrate.
 10. An active matrix liquid crystal display device, comprising: a first substrate provided with a color filter and a second substrate provided with an active matrix array, wherein said first substrate is provided with a laminated colored layer with three colors, a laminate colored layer with two colors, and a colored layer with one color in a frame part surrounding a display area without being provided with a black matrix, and each plane shape of said colored layers with each of three colors is the same.
 11. A manufacturing process of an active matrix liquid crystal display device, comprising: forming a color filter substrate by means of forming a first colored layer using a lithography process with an exposure mask, forming a second color layer using a lithography process with a mask having a same pattern as said exposure mask, and forming a third colored layer using a lithography process with a mask having a same pattern as said exposure mask; forming a conductive film in a region on an array substrate which is opposed to a colored layer with one color and a laminated colored layer with two colors which are located in an outer circumference of a display area on said color filter substrate; sticking said color filter substrate on said array substrate; and sealing a liquid crystal inserted therebetween. 